Gaining legitimate lean muscle tissue is something I rarely see happen. Gaining weight with a mixture or water, body fat and SOME muscle tissue gain is the most common outcome. Why is this so?
I believe it is because there are two parts to this and most people often neglect the fundamentals of health first.
Physiologically speaking the last thing on the bodies priority list to do is gain muscle tissue or lose body fat. This is because everything else in the body must be firing efficiently for your body to attend to such requests. For example here are a few often overlooked factors the produce rapid growth, you could delve in deeper however these are the main variables I consider when working with someone:
Hormonal health factors
General health factors
Lifestyle factors
* Bioprint and thorough blood work is the most comprehensive way to obtain the above data.
The second part is more commonly known and is more about engineering the framework. Below are some of the main considerations I would go through when designing a protocol for lean muscle tissue gain.
Training and program design
Nutrition and supplementation.
If putting on lean muscle tissue is what you desire then be sure to work from the inside out. This way results will manifest fast and will be there to stay as a well designed root-cause solution will always trump any form of short term strategy.